NASA has joined astronaut Randy Bresnik, who is in orbit now, in the waiting game for the birth his daughter, just one day before the spaceflyer is poised to make his first spacewalk.

"There's no word yet," space station flight director Brian Smith told reporters late Friday.

Bresnik is flying on NASA's space shuttle Atlantis, which is docked at the International Space Station to deliver tons of spare parts and other supplies. His wife Rebecca, meanwhile, is here on Earth preparing to give birth to their second child - a baby girl.

NASA officials said the baby's birth was slated for as early as today, while Bresnik and his crewmates delivered a wealth of supplies and performed vital station maintenance. But it could now be tonight or sometime Saturday, when Bresnik and another crewmate are due to step out on their mission's second spacewalk.

Smith said all of NASA is pulling for the Bresnik family, but joked that the baby's delayed arrival has thrown a wrench into NASA's well-oiled shuttle mission plan. He said as much to the flight surgeons at Mission Control in Houston.

"I told them, 'Don't the doctors and Rebecca realize this is NASA and I've got a really well thought out, well-planned, meticulous plan, and they are not abiding by it,'" Smith said with a smile. "But I am not going to be able to control that situation. Rebecca's on her own."

Bresnik and his wife initially believed they could not have a biological child and adopted a son, now 3 1/2, from Ukraine last year. They found out Rebecca was pregnant just a few months later.

In a NASA interview recorded before Atlantis launched Monday, Bresnik and his wife said they planned to induce the baby's birth two weeks early because of medical concerns and hoped that would allow them some leeway in coordinating her arrival to a less-busy time in Bresnik's mission. Bresnik will perform two spacewalks - on Saturday and Monday, respectively - before the mission ends with a post-Thanksgiving landing on Nov. 27.

That may not be the case now. But Smith said that is completely okay.

"We will accommodate whatever Rebecca and her new baby want to do," he said.

Bresnik has said his situation is no different from those experienced by military personnel who are deployed overseas, away from their families.

He is by no means the first parent to fly in space, but he is only the second American to be in orbit while expecting his wife to give birth. NASA astronaut Michael Fincke coached his wife through the birth of their daughter from the space station during his own long-duration flight in June 2004. Fincke met his daughter Tarali Paulina for the first time when she was four months old.

If Bresnik's daughter is born during Saturday's spacewalk, Smith will speak with flight surgeons and draw up a plan for notifying the astronaut. Bresnik will be 100 percent focused on his mission, regardless, Smith said.

"I'm just as interested as everybody else, and I'm hoping that everything just works out perfect for them," Smith said.